Vibration insulating pad

ABSTRACT

A vibration insulating pad through which a center member is elastically connected to a vehicle body in an automotive vehicle. The vibration insulating pad is formed of rubber and to be disposed in an installation hole formed in the center member. The vibration insulating pad comprises a head section and a body section which are coaxially integral with each other through a neck section. A generally annular groove is formed between the head and body sections and around the neck section. An axially extending central through-hole is formed throughout the head, neck and body sections. Additionally, an axially extending slit is continuously formed extending from the inner to outer surfaces of the pad. The slit is located generally tangential with respect to the through-hole thereby facilitating deforming the pad long and narrow by hands of an operator prior to the installation operation for the pad.

This application is a divisional of application Ser. No. 08/858,761filed May 19, 1997, now U.S. Pat. No. 5,871,199 which is a continuationof application Ser. No. 08/209,047 filed Mar. 11, 1994.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to improvements in a vibration insulating padthrough which two vibratory members are supportingly connected, and moreparticularly to such a vibration insulating pad which is formed ofrubber and disposed in a hole formed in a member for supporting a powerunit of an automotive vehicle.

2. Description of the Prior Art

It is well known that there are automotive vehicles provided with acenter member on which a power unit is supported. The center member isdisposed extending in the fore-and-aft direction of the automotivevehicle and elastically supported through vibration insulating pads to avehicle body or frame. Each vibration insulating pad is fitted in aninstallation hole formed in the center member.

The vibrating insulating pad is formed of rubber and generallycylindrical so as to be formed with an axially extending through-hole.The pad includes head, neck and body sections. The head section isformed tapered to facilitate installation of the pad in the installationhole of the center member. A generally annular groove is formed betweenthe head and body section and around the neck section.

However, difficulties have been encountered in the above conventionalvibration insulating pad as discussed below. The vibration insulatingpad is relatively low in spring constant to obtain a sufficientvibration insulating effect, which requires making the pad large-sizedto meet a necessary durability of the pad. Thus, the head section isconsiderably larger in diameter than the installation hole of the centermember and therefore it is impossible to install the pad into theinstallation hole even upon deforming it by hands of an operator. Inthis regard, a pad press-fitting facility such as an air cylinder isrequired for the installation operation for the pad. This isdisadvantageous from the view points of reducing the number of steps ina production process and of production cost for a power unit supportingsystem.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improvedvibration insulating pad which can effectively overcome drawbacksencountered in conventional vibration insulating pads.

Another object of the present invention is to provide an improvedvibration insulating pad which can be installed to a predeterminedposition by hands of an operator without using any press-fittingfacility for the pad.

A further object of the present invention is to provide an improvedvibration insulating pad which can be easily manually fitted in aninstallation hole which has a diameter considerably small as comparedwith the outer diameter of the pad.

A still further object of the present invention is to provide animproved vibration insulating pad which can be easily manually fitted inan installation hole even if the pad takes a variety of shapes otherthan a generally cylindrical shape.

A vibration insulating pad of the present invention is formed of rubberand comprising a generally circular head section. A generallycylindrical neck section is coaxial and integral with the head section.A generally cylindrical body section is coaxial and integral with theneck section A generally annular groove is formed between the head andbody section and around the neck section. An axially extending centralthrough-hole is formed coaxial and extends axially throughout the head,neck and body sections. The central through-hole is defined by an innersurface of the pad. An axially extending slit continuously extends fromthe inner surface to an outer surface of the pad. The slit is defined byfirst and second end faces forming part of the pad, in which at leastone of the first and second end faces is generally parallel with andspaced from a vertical plane containing an axis of the pad.

The thus arranged vibration insulating pad is installed to aninstallation hole of a member in the following manner: First, the pad istwisted vertically around the axially central portion of the slit sothat the end faces respectively displace upwardly and downwardly. Thistwisting action is continued until the end faces are axially separatefrom each other. Then, the pad is twisted around its axis until the endfaces peripherally displace and take a condition that end faces arelocated peripherally opposite relative to their initial positions, uponwhich a part of the upper end of the head section is caught by a part ofthe lower end of the body section. Accordingly, the pad is maintained atits twisted condition. Subsequently, the thus twisted pad is insertedinto the installation hole and rotated upon the groove fitting to aperipheral portion defining the installation hole. Lastly, the part ofthe upper end of the head section caught by the part of the lower end ofthe body section is pushed inside and then outside. Accordingly, thetwisted pad is restored to its initial state thus completing theinstallation operation of the pad to the installation hole.

Thus, the vibration insulating pad can be easily installed or fitted inan installation hole by the hands of the operator without using anypress-fitting facility such as an air cylinder, thus facilitating theinstallation operation for the pad and lowering the production cost of avehicular power unit supporting system.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference numerals designate like elements andparts throughout all figures, in which:

FIG. 1 is a perspective view of an embodiment of a vibration insulatingpad according to the present invention;

FIG. 2 is a plan view of the vibration insulating pad of FIG. 1;

FIG. 3 is a side view of the vibration insulating pad of FIG. 1;

FIG. 4 is an illustration showing a condition in which the vibrationinsulating pad of FIG. 1 is to be installed to a center member;

FIG. 5 is an illustration showing a condition in which the vibrationinsulating pad of FIG. 1 has been installed to the center member;

FIG. 6 is an illustration showing a condition in which the vibrationinsulating pad of FIG. 1 is vertically twisted around the axiallycentral portion of a slit;

FIG. 7 is a perspective view of the vibration insulating pad of FIG. 1in its twisted state in which the pad has been also twisted around itsaxis;

FIG. 8 is a perspective view of the vibration insulating pad as viewedfrom the direction of an arrow C in FIG. 7;

FIG. 9 is a perspective view showing a condition in which the vibrationinsulating pad of FIG. 1 is to be installed to the center member;

FIG. 10 is a perspective view showing a state in which the vibrationinsulating pad of FIG. 1 is being inserted into the installation hole ofthe center member upon being screwed;

FIG. 11 is a perspective view showing a state in which the vibrationinsulating pad at its twisted state is to be restored to its originalstate;

FIG. 12 is a fragmentary perspective view showing a condition in whichthe vibration insulating pad has been installed in position of thecenter member;

FIG. 13 is a perspective view of another embodiment of the vibrationinsulating pad according to the present invention;

FIG. 14 is a plan view of the vibration insulating pad of FIG. 13;

FIG. 15 is a side view of the vibration insulating pad of FIG. 13;

FIG. 16 is an illustration showing a condition in which the vibrationinsulating pad of FIG. 13 is manually installed in position of a centermember;

FIG. 17A is a plan view of an example of the vibration insulating pad,similar to the pad of FIG. 13;

FIG. 17B is a plan view similar to FIG. 17A but showing another example;and

FIG. 18 is a plan view of a modified example of the vibration insulatingpad of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1 to 5, an embodiment of a vibration insulatingpad of the present invention is illustrated by the reference characterP1. As shown in FIGS. 4 and 5, the vibration insulating pad P1 of thisembodiment is used to be fitted in an installation hole 10a formedthrough a wall of a center member 10 of an automotive vehicle (notshown). The center member 10 is located extending in the fore-and-aftdirection of the vehicle and supported through the vibration insulatingpad P1 to a vehicle body or frame (not shown). A power unit including anengine and a transmission is supported on the center member though notshown.

The vibration insulating pad P1 is formed of rubber or elastomericmaterial and formed generally cylindrical to have a generallycylindrical axially extending central through-hole 1 in which a bolt(not shown) is disposed to connect the center member 10 to the vehiclebody through the vibration insulating pad P1. The vibration insulatingpad P1 comprises a generally frusto-conical head section 2 which isformed with a through-hole la forming part of the centralthrough-hole 1. The through-hole 1a is coaxial with the head section 2.The head section 2 is formed with a frusto-conical surface 2a which istapered toward the free or upper end (not identified) of the headsection 2. A flat cylindrical neck section 4 is integral at its upperend with the lower end of the head section 2 and located coaxial withthe head section 2. The neck section 4 is formed with a through-hole 1bforming part of the axially extending central through-hole 1, and has anouter diameter smaller than the outer diameter of the head section 2.Additionally, a generally cylindrical body section 3 is integral at itsupper end with the lower end of the neck section 4 and located coaxialwith the neck section 4. The body section 3 is formed with athrough-hole 1c forming part of the axially extending centralthrough-hole 1, and formed with a cylindrical peripheral surface 3awhose outer diameter is larger than that of the neck section 4 andgenerally equal to that of the head section 2. It will be understoodthat the through-holes 1a, 1b, 1c have the same diameter and coaxial andaxially aligned with each other to form the axially extending centralthrough-hole 1. It will be understood that the axially extending centralthrough-hole 1 is defined by the inner surface S1 of the pad P1.

The head section 2 is formed at its lower end with an annular flat face2b which is perpendicular to the center axis A of the pad P1 and extendsradially outwardly from the outer peripheral surface of the neck section4. The body section 3 is formed at its upper end with an annular flatface 3b which is parallel with the annular flat face 2b of the headsection 2 and extends radially outwardly from the outer peripheralsurface of the neck section 4. A generally annular groove G is definedby the flat faces 2b, 3b and the outer peripheral surface of the necksection 4. It will be understood that the a peripheral portion 10b(defining the installation hole 10a) of the center member 10 is fittedin the annular groove G as shown in FIG. 5.

An axially extending slit 5 is formed in the vibration insulating pad P1in such a manner as to extend from the outer surface S2 to the innersurface S1 of the pad P1, so that the generally cylindrical pad P1 hasperipherally opposite end faces E1, E2 which define the slit 5, as shownin FIGS. 6 and 7.

It will be understood that the end faces E1, E2 face to each other andmay be in contact with each other in a state of FIGS. 1 to 5. It is tobe noted that the slit 5 extends parallel with an imaginary verticalplane V (shown in FIG. 2) which contains the center axis A of the padP1, and located slightly spaced from the vertical plane V. In otherwords, the slit 5 is formed generally tangential relative to the axiallyextending central through-hole 1 particularly as viewed from thedirection of the axis A as illustrated in FIG. 2.

The manner of installation of the above vibration insulating pad P1 tothe center member 10 will be discussed hereinafter in the order of stepsof an installatin process with reference to FIGS. 6 to 12.

First, the vibration insulating pad P1 is twisted vertically around thecentral portion of the slit 5 by hands of an operator so that the endfaces E1, E2 respectively displace upwardly and downwardly or inopposite directions to each other as indicated by arrows in FIG. 6. Thistwisting action is continued until the end faces E1, E2 are brought intosuch a condition as to be axially separate from each other so that apart of the upper end of the head section 2 is below a part of the lowerend of the body section 3.

Then, as shown in FIG. 7, the pad P1 is twisted around its axis untilthe the end faces E1, E2 are peripherally displaced and brought intosuch a such a condition that the end faces E1, E2 are respectivelypositioned at opposite sides relative to their initial positions shownin FIG. 6. At this condition, the operator releases his hands from thethus twisted pad P1, upon which the part of the upper end of the headsection 2 is caught by the part of the lower end of the body section 3.As a result, the pad P1 is maintained at its vertically twisted statethereby forming a twisted vibration insulating pad P1' as shown in FIGS.7 and 8. In this state, the groove G between the head and body sections2, 3 takes a helical form.

Subsequently, as shown in FIG. 9, the tip end portion (defined by theend face E1) of the head section 2 of the twisted pad P1' is insertedinto the installation hole 10a of the center member 10, and then the tipend part of the groove G is fitted to the inner edge 10c of theperipheral portion 10b defining the installation opening 10a by the handof the operator. The twisted pad P1' is rotated under a state in whichthe groove G and the peripheral portion inner edge 10c are being fittedwith each other, as shown in FIG. 10. Under the screwing action of thetwisted pad P1', the twisted pad P1' is gradually upwardly displacedrelative to the inner edge 10c defining the installation hole 10a of thecenter member 10 so that the upper part of the twisted pad P1' isreached to a set state while the lower part of the same is left at aunset state.

Lastly, as shown in FIG. 11, the part of upper end of the head section 2caught by the part of the lower end of the body section 3 is pushedinside and then outside, and accordingly the twisted pad P1' is restoredto its initial shape under the action of a rubber elasticity therebyforming the pad P1 as shown in FIG. 12, thus completing the installationoperation of the vibration insulating pad P1 to the installation hole10a of the center member 10.

Next, reasons why the slit 5 is positioned generally tangentiallyrelative to the axially extending central through-hole 1 will bediscussed.

If the slit 5 is formed not generally tangential or on the verticalplane V (in FIG. 2), the following drawbacks are encountered: Eventhough the pad P1 is twisted around the central portion of the slit 5 asshown in FIG. 6 and then twisted around its axis A in the manner shownin FIG. 7, the part of the upper end of the head section 2 cannot becaught by the part of the lower end of the body section 3. As a result,the pad P1' in the twisted state as shown in FIGS. 7 and 8 cannot beobtained. Additionally, when the part of the upper end of the headsection 2 caught by the part of the lower end of the body section 3 ispushed inside and then outside lastly in the manner shown in FIG. 11,the end faces E1, E2 defining the slit 5 interfere with each other andtherefore the caught part of the upper end of the head section 2 cannotbe moved outside.

As appreciated from the above, the vibration insulating pad P1 of theembodiment can be easily installed or fitted in an installation hole byhands of an operator without using any press-fitting facility such as anair cylinder, thus facilitating the installation operation for the padand lowering the production cost of a vehicular power unit supportingsystem.

FIGS. 13 to 16 illustrate another embodiment of the vibration insulatingpad P2 of the present invention, which is similar to the pad P1 of theembodiment of FIGS. 1 to 12 except for the shape of the axiallyextending slit 5'. In this embodiment, the slit 5' is of an axiallyextending cutout of the generally wedge-shape. More specifically, asbest seen from FIG. 14, the slit or cutout 5' is defined by the endfaces E1, E2 of the pad P2. The end face E1 is generally in an imaginaryvertical plane V1 containing the axis A, and therefore extends generallyradially outwardly. The end face E2 is parallel with and spaced from thevertical plane V containing the axis A.

The vertical planes V1 and V form therebetween an angle of 45°, so thatthe end faces E1, E2 form therebewteen the same angle. Thus, thegenerally cylindrical vibration insulating pad P2 of this embodimenttakes the form wherein a generally wedge-shaped part 5' is cut out.

The vibration insulating pad P2 of this embodiment is installed into theinstallation hole 10a in a similar manner to that in the embodiment ofFIGS. 1 to 12, as follows: As shown in FIG. 16, after the pad P2 istwisted to take its twisted state P2', the twisted pad P2' is insertedinto the installation hole upon the groove 4 being in engagement withthe edge 10c defining the installation hole 10a of the center member 10.Under the screwing action, the twisted pad P2' is gradually movedupwardly and deeply inserted in the installation hole 10a.

By virtue of the slit or cutout 5', the amount of twist of the pad 5'around the axis is large as compared with that in the embodiment ofFIGS. 1 to 12, so that the outer diameter of the twisted pad P2' isreduced thereby further facilitating the installation operation for thepad P2 into the installation hole 10a.

In this regard, in case that the head section 2 of the pad P2 has anouter diameter considerably larger than the diameter of the installationhole 10a and additionally is considerably large in radial thickness, thevolume of the cutout 5' is set considerably large as shown in FIG. 17Athereby allowing the pad to be manually installed in position. In caseof the head section 2 has an outer diameter not so larger than thediameter of the installation hole 10a and additionally is small inradial thickness, the volume of the cutout 5' is set small as shown inFIG. 17B thereby allowing the pad P2 to be manually installed inposition.

FIG. 18 illustrates a modified example of the vibration insulating padP2' of the embodiment of FIGS. 13 to 17B. The vibration insulating padP2' of this example is similar to that of the embodiment of FIGS. 13 to17B except for the shape of the cross-section perpendicular to the axisthereof. The pad P2' is generally oval-shaped in cross-section andformed with the generally wedge-shaped slit or cutout 5'. It will beunderstood from this example that pads having a variety ofcross-sectional shapes other than a circular shape can be easilymanually installed in position by virtue of the slit or cutout 5'.

While preferred embodiments have been described, variations thereto willoccur to those skilled in the art within the scope of the presentinventive concepts which are delineated by the following claims. Forexample, in order to further facilitate the installation operation ofthe vibration insulating pad P1, P2, P2', it will be appreciated thatthe peripheral edge portion 2e may be cut out to reduce the outerdiameter of the head section 2 as shown in FIG. 15, or otherwise theouter periphery of the head section 2 may be partly formed arcuate.

What is claimed is:
 1. A vibration insulating pad formed of rubber andcomprising:a generally circular head section; a generally cylindricalneck section which is coaxial and integral with said head section; agenerally cylindrical body section which is coaxial and integral withsaid neck section; a generally annular groove between said head and bodysections and around said neck section; an axially extending centralthrough-hole which extends axially throughout said head, neck and bodysections, said central through-hole being defined by an inner surface ofsaid pad; and an axially extending slit which continuously extends fromthe inner surface to an outer surface of said pad, said slit beingdefined by first and second end faces, the first end face extendinggenerally radially outwardly, the second end face extending generallyparallel with and spaced from a first vertical plane containing an axisof said pad so as to form said slit in a generally wedge-shape; whereinsaid first and second end faces intersect at a position close to saidthrough-hole, and the pad is deformable to take a deformed state inwhich an upper end of one of said first and second end faces disposedbelow is engaged with a lower end of the other of said first and secondend faces.
 2. A vibration insulating pad as claimed in claim 1, whereinsaid head section has a generally frustoconical surface forming part ofthe outer surface of said pad, the frustoconical surface being coaxialwith said head section.
 3. A vibration insulating pad as claimed inclaim 1, wherein said pad is annular in cross-section perpendicular tothe axis of said pad.
 4. A vibration insulating pad as claimed in claim1, wherein said pad is generally oval-shaped in cross-sectionperpendicular to the axis of said pad.
 5. A vibration insulating pad asclaimed in claim 1, wherein the first end face is generally in a secondvertical plane containing the axis, the first and second vertical planesforming therebetween an angle.
 6. A vibration insulating pad as claimedin claim 1, wherein the upper end of the one of said first and secondend faces comprises means for temporarily locking the lower end of theother of said first and second end faces to temporarily lock said pad ina deformed configuration.
 7. A vibration insulating pad as claimed inclaim 6, wherein the pad is adapted for disposition in an opening formedin a structural member, and wherein, in the deformed state, the pad isconstructed to assume an essentially helical configuration whichfacilitates its insertion into the opening.
 8. A vibration insulatingpad formed of rubber and comprising:a shaped, generally cylindrical bodyhaving an axially extending essentially coaxial through-hole, said bodyhaving a head section, a neck section that is coaxial and integral withsaid head section, and a body section that is coaxial and integral withsaid neck section, said body including a generally annular groovebetween said head section and said body section and around said necksection; an axially extending slit which continuously extends from thethrough-hole to an outer surface of said pad, said slit defining firstand second end faces in said pad, one of said first and second end facesbeing generally parallel with and spaced from a first vertical planecontaining an axis of the through-hole; and means for facilitatinginsertion of said pad into an opening in a deformed state, comprising:an upper edge portion of one of said first and second end faces whichis, upon resilient distortion of the pad which moves the first andsecond end faces in opposite directions essentially in the direction ofthe first vertical plane, temporarily engaged with and disposed below alower surface portion adjacent an edge portion of the other of saidfirst and second end faces, to temporarily maintain the pad in anessentially helical configuration which temporarily reduces the diameterof the pad and facilitates insertion of the pad into the opening.
 9. Avibration insulating pad as claimed in claim 8, wherein another of saidfirst and second end faces lies on a second plane which contains theaxis of the through-hole.
 10. A method of disposing a vibration dampingpad in an opening, the pad having an axially extending centralthrough-hole which extends axially through the pad, the pad having ahead section, a neck section that is coaxial and integral with the headsection, and a body section that is coaxial and integral with the necksection, the pad including a generally annular groove between the headsection and the body section and around the neck section, and an axiallyextending slit which continuously extends from the axially extendingthrough-hole to an outer surface of the pad to define juxtaposed firstand second end faces, one of the first and second end faces beinggenerally parallel with and spaced from a first plane containing an axisof the through-hole, another of said first and second end faces lying ona second plane which contains the axis of the through-hole, comprisingthe steps of:distorting the pad so that the first and second end facesare separated with respect to one another essentially in the directionof the first plane; temporarily locking the pad in a distortedconfiguration by engaging an upper corner portion of the first end facewith a surface portion of the pad adjacent a lower edge portion of thesecond end face; inserting the pad into the opening; and releasing thetemporary locking engagement between the upper corner portion and thelower corner portion to allow the damper to reassume its normalconfiguration.
 11. A method as claimed in claim 10, further comprisingthe step of forming the second end face so as to be at an angle withrespect to the first end face and to define a generally wedge-shapedslit.
 12. A method as claimed in claim 11, wherein the second end facelies on a second plane which includes the axis of the through-hole. 13.A method as claimed in claim 10, wherein the vibration damping pad has agenerally oval-shaped cross-section.